The projection display apparatus enables an image supplied from a personal computer to be displayed as an enlarged image on a projection screen and is therefore often used for presentations. In the course of a presentation, a plurality of presentation sheets (hereinafter may be referred to as “slides”) are sequentially changed for display on the projection screen.
With a prior art projection display apparatus a user changes over the presentation sheets. More specifically, the presentation sheets are changed over according to the user's instruction input through the key operation into the computer. Connection of the computer is thus essential for the prior art projection display apparatus.